Cardiovascular System

Question 1

What structures does the blood flow through to the heart?

Answer 1

Great veins (venae cavae on the right and the pulmonary vein on the left) –> Atria –> Ventricles –> Great Arteries (pulmonary artery on the right and the aorta on the left)

Question 2

What are the two sets of valves on each side of the heart?

Answer 2

Atrioventricular and semilunar valves. They direct blood flow to the next structure and prevent backflow.

Question 3

The atrioventricular valves connect the atria and ventricles. What are the two atrioventricular valves and what side of the heart are they in?

Answer 3

The tricuspid valve is on the right side and the bicuspid/mitral valve are on the left side

Question 4

How does the pulmonary circuit work? Include details of the valves

Answer 4

The blood comes into the right atrium through the vena cava into the right ventricle where the tricuspid valve is which is then pushed into the pulmonary arteries in the lungs. From there they pick up oxygen in the lungs the blood travels lack to the heart through the pulmonary veins into the left atrium and then to the left ventricle (where the bicuspid/mitral valve is) and out to the body’s tissues via the aorta.

Question 5

What is it called when the heart is in a contractile state?

Answer 5

Systole

Question 6

What is it called when the heart is in a relaxed state?

Answer 6

Diastole

Question 7

What are the 3 stages of the cycle of the heart?

Answer 7

Atrial Systole = Contraction of the atria
Ventricular Systole = Contraction of the ventricles
Diastole = Relaxation of both the atria and ventricles

Question 8

When do the valves open or close?

Answer 8

Valves open when the chamber before it has a higher pressure than the chamber it’s going into; this prevents backflow due to pressure difference.

Question 9

When do the atrioventricular valves open?

Answer 9

During atrial systole so blood can enter the ventricles

Question 10

When do atrioventricular valves close?

Answer 10

During ventricular systole

Question 11

When do the semilunar valves open?

Answer 11

During ventricular systole so that blood can leave the heart through the great arteries (otherwise it would re-enter the atria).

Question 12

What is after-load?

Answer 12

How much pressure needs to be put on the blood for it to leave the system AFTER ventricular systole

Question 13

What is pre-load?

Answer 13

The force that stretches the cardiac muscle prior to contraction BEFORE ventricular systole

Question 14

What can an ECG tell us?

Answer 14

If someone has too high sodium or potassium. It can also look at pressure and force.

Question 15

What’s the sinoatrial node (SAN)?

Answer 15

Pacemaker of the heart. Self-contractile but the brain can tell it whether to speed up or slow down. It’s a group of cells found high in the right atrium close to the junction in the superior vena cava. Stimulates atrial myocardium to contract.

Question 16

What is the antrioventricular node (AVN)?

Answer 16

Receives electrical impulses from the atria and then transmits the electrical impulse from the atria to the ventricles.

Question 17

What’s the Bundle of His?

Answer 17

Receives input from the atrioventricular node (AVN) and propagate impulses to the left and right ventricles. Each of the branches end in Purkinje Fibres.

Question 18

What is Frank-Starling Law?

Answer 18

The more blood in the heart during systole is equal to how much blood goes back to the heart during diastole

Question 19

What are the 2 cardiac volumes during the cardiac cycle? And what are they for?

Answer 19

Ventricular End-Systole Volume and Ventricular End-Diastic Volume
Volumes used to calculate other parameters that are indicative of cardiac function

Question 20

What is ventricular end-systole volume?

Answer 20

Volume of blood in the ventricle after systole

Question 21

What is ventricular end-diastic volume?

Answer 21

Volume of blood after diastolic systole

Question 22

What is stroke volume?

Answer 22

The volume of blood ejected from the heart in one cardiac cycle

Question 23

How is stroke volume calculated?

Answer 23

In ml
left ventricular end-diastolic volume - left ventricular end-systolic volume

Question 24

What is cardiac volume?

Answer 24

Total volume of blood that’s pumped through the heart per minute

Question 25

How is cardiac volume/output calculated?

Answer 25

In ml/min
Stroke volume x heart rate (beats per min)

Question 26

What is the ejection fraction?

Answer 26

Demonstrates the % of blood the heart receives that’s ejected during systole

Question 27

How is the ejection fraction calculated?

Answer 27

In %
Stroke volume / left ventricular end-diastolic volume

Question 28

What vessels does the blood follow after going after left ventricle contraction?

Answer 28

Arteries (thick outer walls and small lumen) –> arterials (narrower that can be told to get dilated or constricted in response to blood pressure) –> capillaries (where they leave and perfuse the particular organs so are one-cell thick, collapse when BP drop) –> venules in the venus system (veins, have valves, have reverse pressure to suction blood to the heart).

Question 29

What is total peripheral resistance (TPR)?

Answer 29

The amount of force that’s exerted on circulating blood by the vasculature of the body. It’s mainly determined by the arterioles of how dilated or constricted they are in response to BP.

Question 30

What is mean arterial pressure (MAP)?

Answer 30

The driving force for blood flow and if it drops organs risk being underperfused.

Question 31

How do you calculate Mean arterial Pressure (MAP)?

Answer 31

Co x TPR

MAP changes depending on signals from baroreceptors and RAAS system

Question 32

What are the artery branches off the arch of aorta?

Answer 32

Brachiocephalic artery branches to the right subclavian artery and right common carotid artery
The left subclavian artery and the left common carotid artery come directly off the arch of aorta

Question 33

What’s the RAAS system?

Answer 33

The kidney senses a drop in blood pressure the kidney releases renin which stimulates angiotensinogen and 1 is converted into angiotensin 2 by ACE from the lungs which causes vasoconstriction leading to blood pressure rises. It also activates aldosterone (in the adrenal coretex) which causes posterior pituitary to release ADH/Vasopressin which holds on to H2O and Na+ but loses K+ which results in sodium retention and therefore an increase in blood pressure.

Question 34

What does the left atrium heart feed into and what percentages are these?

Answer 34

25% skeletal muscle, gastrointestinal and renal
15% cerebral
5% coronary and skin